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| Titel |
Operational assimilation of ASCAT surface soil wetness at the Met Office |
| VerfasserIn |
I. Dharssi, K. J. Bovis, B. Macpherson, C. P. Jones |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 15, no. 8 ; Nr. 15, no. 8 (2011-08-31), S.2729-2746 |
| Datensatznummer |
250012938
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| Publikation (Nr.) |
 copernicus.org/hess-15-2729-2011.pdf |
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| Zusammenfassung |
| Currently, no extensive, near real time, global soil moisture observation network
exists. Therefore, the Met Office global soil moisture analysis scheme
has instead used observations of screen temperature and
humidity. A number of new space-borne remote sensing systems,
operating at microwave frequencies, have been developed that provide
a more direct retrieval of surface soil moisture. These systems are
attractive since they provide global data coverage and the horizontal
resolution is similar to weather forecasting models. Several studies
show that measurements of normalised backscatter (surface soil
wetness) from the Advanced Scatterometer (ASCAT) on the meteorological
operational (MetOp) satellite contain good quality information about
surface soil moisture. This study describes methods to convert ASCAT
surface soil wetness measurements to volumetric surface soil moisture
together with bias correction and quality control. A computationally
efficient nudging scheme is used to assimilate the ASCAT volumetric
surface soil moisture data into the Met Office global soil moisture
analysis. This ASCAT nudging scheme works alongside a soil moisture
nudging scheme that uses observations of screen temperature and
humidity. Trials, using the Met Office global Unified Model, of the
ASCAT nudging scheme show a positive impact on forecasts of screen
temperature and humidity for the tropics, North America and
Australia. A comparison with in-situ soil moisture measurements from
the US also indicates that assimilation of ASCAT surface
soil wetness improves the soil moisture analysis. Assimilation of
ASCAT surface soil wetness measurements became operational during July
2010. |
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